The bumpy light curve of Type IIn supernova iPTF13z over 3 years

Creators: Nyholm, A.; Sollerman, J.; Taddia, F.; Fremling, C.; Moriya, T. J.; Ofek, E. O.; Gal-Yam, A.; De Cia, A.; Roy, R.; Kasliwal, M. M.; Cao, Y.; Nugent, P. E.; Masci, F. J.

Abstract

A core-collapse (CC) supernova (SN) of Type IIn is dominated by the interaction of SN ejecta with the circumstellar medium (CSM). Some SNe IIn (e.g. SN 2006jd) have episodes of re-brightening ("bumps") in their light curves. We present iPTF13z, a Type IIn SN discovered on 2013 February 1 by the intermediate Palomar Transient Factory (iPTF). This SN showed at least five bumps in its declining light curve between 130 and 750 days after discovery. We analyse this peculiar behaviour and try to infer the properties of the CSM, of the SN explosion, and the nature of the progenitor star. We obtained multi-band optical photometry for over 1000 days after discovery with the P48 and P60 telescopes at Palomar Observatory. We obtained low-resolution optical spectra during the same period. We did an archival search for progenitor outbursts. We analyse the photometry and the spectra, and compare iPTF13z to other SNe IIn. In particular we derive absolute magnitudes, colours, a pseudo-bolometric light curve, and the velocities of the different components of the spectral lines. A simple analytical model is used to estimate the properties of the CSM. iPTF13z had a light curve peaking at Mr ≲ − 18.3 mag. The five bumps during its decline phase had amplitudes ranging from 0.4 to 0.9 mag and durations between 20 and 120 days. The most prominent bumps appeared in all the different optical bands, when covered. The spectra of this SN showed typical SN IIn characteristics, with emission lines of Hα (with broad component FWHM ~ 10^3 – 10^4 km s^(-1) and narrow component FWHM ~ 10^2 km s^(-1)) and He I, but also with Fe II, Ca II, Na I D and Hβ P Cygni profiles (with velocities of ~ 10^3km s^(-1)). A pre-explosion outburst was identified lasting ≳ 50 days, with M_r ≈ − 15 mag around 210 days before discovery. Large, variable progenitor mass-loss rates (≳0.01M⊙ yr^(-1)) and CSM densities (≳10^(-16) g cm^(-3)) are derived. The SN was hosted by a metal-poor dwarf galaxy at redshift z = 0.0328. We suggest that the light curve bumps of iPTF13z arose from SN ejecta interacting with denser regions in the CSM, possibly produced by the eruptions of a luminous blue variable progenitor star.

Additional Information

© 2017 ESO. Article published by EDP Sciences. Received 14 October 2017; Accepted 24 March 2017; Published online 29 August 2017. Thanks to John Telting, Auni Somero, Paul Vreeswijk, Ofer Yaron, Kunal Mooley, Ragnhild Lunnan, Danny Khazov, and Gina Duggan for making observations of iPTF13z. Thanks to Peter Lundqvist and Mattias Ergon for discussions. Thanks to Andrew Drake and Ashish Mahabal for assisting with access to the Catalina Real-time Transient Survey images. We gratefully acknowledge the support from the Knut and Alice Wallenberg Foundation. The Oskar Klein Centre is funded by the Swedish Research Council. This research used a computer bought with a grant from the Alva and Lennart Dahlmark Foundation. T.J.M. is supported by the Grant-in-Aid for Research Activity Start-up of the Japan Society for the Promotion of Science (16H07413). EOO is the incumbent of the Arye Dissentshik career development chair and is grateful for support by grants from the Willner Family Leadership Institute Ilan Gluzman (Secaucus NJ), Israel Science Foundation, Minerva, Weizmann-UK, and the I-Core program by the Israeli Committee for Planning and Budgeting and the Israel Science Foundation (ISF). A.G.Y. is supported by the EU/FP7 via ERC grant No. 307260, the Quantum Universe I-Core program by the Israeli Committee for planning and funding, and the ISF, Minerva and ISF grants, WIS-UK "making connections", and Kimmel and YeS awards. The intermediate Palomar Transient Factory (iPTF) project is a scientific collaboration among the California Institute of Technology, Los Alamos National Laboratory, the University of Wisconsin, Milwaukee, the Oskar Klein Centre, the Weizmann Institute of Science, the TANGO Program of the University System of Taiwan, and the Kavli Institute for the Physics and Mathematics of the Universe. This research used resources of the National Energy Research Scientific Computing Center, a DOE Office of Science User Facility supported by the Office of Science of the US Department of Energy under Contract No. DE-AC02-05CH11231. This work was supported by the GROWTH project funded by the National Science Foundation under Grant No. 1545949. This research used observations made with the Nordic Optical Telescope, operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias. This research used observations obtained with the Apache Point Observatory 3.5-m telescope, which is owned and operated by the Astrophysical Research Consortium. Some of the data presented here were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration (NASA). The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognise and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. This research used the SIMBAD and VizieR databases operated at CDS, Strasbourg, France. This research used the NASA/IPAC Extragalactic Database (NED) which is operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. This research used NASA's Astrophysics Data System.

Attached Files

Published - aa29906-16.pdf

Submitted - 1703.09679.pdf

Files

1703.09679.pdf

Files (2.9 MB)

Name	Size	Download all
1703.09679.pdf md5:3c620a922e0add0031fbe1e7325298b1	1.6 MB	Preview Download
aa29906-16.pdf md5:c07930025fbdfdb32f9e3c3fca55bcb2	1.3 MB	Preview Download

Additional details

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes